Resinous interpolymer containing 1, 2-dicyano-1-phenylethylene



Patented Aug. 24, 1948 UNITED. STATE RESINOUS INTERPOLYMER CONTAINING LZ-DICYANO-l-PHENYLETHYLEBIE David T. Mowry, Dayton, out, asa ignor to Mon-. santo Chemical Company, St. Louis, Mo.. a cofporation of Delaware No Drawing. Application Jilly 24, 1944,

I Serial No. 546,434

The present invention relates to the production of copolymerization (e. g., coor interpolymerization) products.

An object of the present invention is to provide copolymerization pro'ducts'oi CH: C substituted aromatic hydrocarbons such as styrene, alpha-methylstyrene and alpha,para-dimethylstyrene, together with 1,2-dicyano-1-phenylethylene, which products have improved physical strength characteristics, as well as a higher thermal stability (heat distortion point) than does the polymerized vinyl aromatic hydrocarbon itself.

I have foundthat valuable interpolymerization products may be obtained by polymerizin a mixture containing ,1,2 dicyano 1 phenylethylene and a CH2=C substituted aromatic hydrocarbon V such as styrene, alpha-methylstyrene oralpha, para-dimethylstyrene. I! desired, mixtures of the latter three CH2=C substituted aromatic Q When the evolution of HCl-gas has ceased the product is recovered in good yield from the residue by distillation under high vacuum.- It may be further purified by crystallization from dilute alcohol if desired.

Polymerization of the above-mentioned compounds to form interpolymers may becarried out by merely heating ,a mixture of the nitrile and the CH2=C substituted aromatic hydrocarbon in mass, in solution or in emulsion. The temperature of polymerization may range from 50 C. to 120 (7., although in some cases higher temperatures may be satisfactorily employed.

When carrying out 'a mass polymerization of the above-mentioned ingredients, 9. mixture is first prepared by dissolving the nitrile in theliquid monomeric CH2=C substituted aromatic hydrocarbon and the mixture then subjected to 5 Claims. (01. 260-785) dinitrile being readily recoverable in unpolymer-' ized form. g

The amount of 1,2-dicyano-l-phenylethylene combined as interpolymer may vary from 1% to 50% by weight of the interpolymer, the amount many vinyl compounds such as vinyl chloride,

vinyl esters such as vinyl acetate or vinyl ethers.

The present interpolymers may be readily obtained in a clear, transparent and chemically stable form. The present products may be employed for the production of transparent objects such as interlayers for safety glass or the like, or

The present interpolymers are, moreover, characterized by good resistance to chemical reagents,

excellent thermal stability and improved. resistance to impact. In general, the copolymerization of v ethylene in the proportions so as to yield from, say, 5% to 35% by weight of the'copolymerized- 1,2-dicyano'-l-phenylethylene in the interpolymer styrene with 1,2-dicyano-1-pheny1- disclosed in the copend'in application of Reid G. f I ordyce, Serial No. 503,941, filed September 27,

1943, now abandoned, which application is assigned to the same assignee as the present applipolymerizing conditions by the application of cation.

For the production of clear, transparent, resinous products derived from monomeric styrene, I may employ mixtures of monomeric styrene and 1, 2-dicyano-l-phenylethylene, in which mixtures the nitrile content is below approximately 50% by weight and preferably below 35% by weight of said mixture. During polymerization by mass or solution methods, and depending upon the relative proportions of the dinitrile and CH2=C substituted aromatic hydrocarbon present in the mixture undergoing polymerization, one of the constituents thereof will enter the growing polymer chain at a greater rate than the other constituent. It may, accordingly, be desirable during polymerization to maintain constant the concentration of the constituent which enters the 3 copolymer at the highest rate. This may be done, as described in the above-mentioned application, Serial No. 508,941, by a determination of resinous material isobtained which is substan:

tially free from monomeric material. Such a method is useful when producing cast objects. For most purposes, however, the polymerization is generally cai'ried to a degree which is short of complete polymerization and the interpolymer thereafter recovered by solution in a solvent such as benzol or dioxane, which solution is then poured into a lower aliphatic alcohol wherein the interpolymer is insoluble and inwhich the unpolymerized monomeric materials are soluble. Such a procedure results in the production 01 a finely divided powdery 'to fibrous, colorless to. a

By the use of suitable amounts of solvent, the

slightly yellowish material which may be washed iree oi adhering monomeric materials and solvent, dried and which then is suitable for use as a molding material;

The invention is further illustrated by means 0! the i'ollowin'g examples which are given for the purposes of illustration and are not to be considered as limitations upon the present inve'ntion.

Example 1 I poured into methyl alcohol. The interpoiymer will be recovered in the form of a white, some what fibrous, solid material. The powdery material is then molded by compression molding in a heated die, and will be found to have an ASTM heat distortion point substantially higher than that of polystyrene.

. In place of styrene, alpha-methylstyrene or alpha, para-dimethylstyrene or mixtures thereof, with styrene, may be employed.

Example 2 A monomeric mixture of styrene and 1,2-dicyano-l phenylethylene, said mixture containing approximately 2.5% of the dinitrile is polymerized by heating in .the presence 01 a polymerization'catalyst to a temperature of 50 C. to

' 60 C. with stirring. During the polymerization,

samples of the mixture maybe withdrawn and the content of copolymer in the mixture determined by precipitation in alcohol. The content of the dinitrile in the polymer may be determined by analysis ofits nitrogen content.

Based upon the analysis the amount and composition of the copolymer may be determined as well as the concentration of the dinitrile in the monomeric mixture. As a result of such an analysis the amount of interpolymer present, as

the monomeric mixture containing the same, may be determined. Based upon such a determination conducted at frequent intervals during polymerization, the monomeric mixture may be ad- Justed to that originally present and the composition or the copolymer with respect to dinitrile maintained at a substantially" constant value throughout the polymerization.

When polymerizations are carried out as above-described, i. e., in the absence of a solvent.

the degree of polymerizationmay be carried to the point where the mixture contains between, say, 20% and 30% by weight of the interpolymer. At this point the viscosity ordinarily becomes too high for the maintenanceoi uniformity and the polymerization may be interrupted and the interpolymer recovered by solution in a solvent followed by precipitation by addition of the mixture to alcohol. I

If desired, the polymerization maybe carried out in solution in -a solvent such as benzol or dioxane, in which case the polymerization may be carried to a greater content of copolymer than was possible in the absence of the solvent.

extent of polymerization may be carried to 60% to 70%; completion. The polymeric material is recovered by precipitation in alcohol. In this manner, moldable interpolymer, which is clear and homogeneous may be obtained.

The behavior towards solvents of the resinous interpolymer depends upon the amount of copolymerized 1, 2-dicyano-l-phenylethylene contained therein. -In general, increasing the amount of '1,2-dicyano-1phenyiethylene, in the interpolymer increases its resistance to solvents.

The 'interpolymerization oi the CH1=C sub- 'stituted aromatic compound and l,2-dicyano-lphenyiethylene may also be carried out in the 40 presence of plasticizers and plasticized resinous bodies obtained.

Example 3 A mixture comprising 70 g. of styrene, 30 g of 1,2-dicyano-l-phenylethylene and 30 g. of

butyl phthalyl butyl glycollate is polymerized by heating at a temperature of 80 C. for 15 days and then at 120 C. for one day. The resulting hard, clear resin is ground to a powder and then milled on heated rolls. If desired, coloring mat:

ter may :be added, while'miliing. The milled ma terial is then reduced to a-powder and maybe molded in heated dies for the production of various objects.

Various other proportions of a CH:=C subployed in a similar manner.

Example 4 f A mixture consisting of 85 g. of monomeric styrene and 15 g. 1,2-dicyano-l-phenylethyienc is emulsified to a line milk in 120 g. oi water containing 3.0 g. of disodium phosphate, 0.8 g.

of citric acid and 0.04 g. of potassium persuliate and also containing 12.5 g. oi sodium lorol sulfate as an emulsifying agent. The pH of the emulsion is about 5.0. The emulsion is polymerized by refluxing (boiling under a reflux condenser for 15 minutes). The emulsion is then broken by pouring into methyl alcohol and the precipitated polymer is filtered, washed with alwell as the composition 01' the interpolymer and cohol and water and then dried. Alternatively v 5 the emulsion may be broken by adding a solution of an electrolyte.

The dried. finely divided polymer, containing approximately 15% by weight of 1,2-dicyano-1- phenylethylene, may then be used directly as a molding powder, or it may be milled on heated rolls, the sheet thus obtained comininutedand employed in molding operations.

The herein-described interpolymers are resistant to acids and alkalies, i. e., there is no tendency of the nitrile groups in the interpolymer to hydrolyze. The present products are insoluble in dilute or concentrated acids and in dilute or concentrated aqueous aikalies. They. are free from carboxy groups and also salt groups.

This application is a continuation-in-part oi my copending application Serial No. 450,514, tiled July 11, 1942, now abandoned.

What I claim is:

1. The process which comprises forming a polymerizable mixture consisting oi a CH::C substituted aromatic hydrocarbon selected from the group consisting of styrene, alpha-methyistyrene and alpha,paradimethylstyrene, together with 1,2-dicyano-l-phenylethylene, said mixture containing between 0.5% and 50% by weight of said 1,2-dicyano-l-phenyiethylene and then heating said mixture to a polymerizing temperature to form an interpoiymer.

2. The process which comprises forming a mixture consisting of styrene and 1,2-dicyano-1- phenylethylene the latter comprising from 0.5% to 50% by weight of said mixture, and then heating said mixture to. a polymerizingtemperature to form an interpolymer.

\ 3. A resinous material comprising an interpolymer of styrene and 1,2-dicyano-l-phenylethylone, said interpolymer containing between 5.0% and 35% oi. copolymerized 1,2-dicyano-1-phenylethylene the balance thereof being copolymerized styrene,

4. A resinous material comprising an interpolymer of styrene and 1,2-dicyano-1-phenylethylene, said interpolymer containing 15% of 10 copolymerized 1,2-dicyano-l-phenylethylene the balance thereof being copolymerized styrene.

5. A resinous material comprising an interpolymer consisting of a CH==C substituted aromatic hydrocarbon selected from the group consisting of styrene, alpha-methylstyrene and alpha,para-dimethylstyrene copolymerized with 1,2-dlcyano-l-phenylethylene, said interpolymer containing between 1.0% and 50% oi. copolymerized 1,2-dicyano-1-phenylethylene.

DAVID '1. MOWRY.

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